<template>
  <el-container class="home-container">
    <!-- 头部区域 -->
    <el-header>
      <div>
        <img src="../assets/heima.png" alt="">
        <span>电商后台管理系统</span>
      </div>
      <el-button type="info" @click="logout">退出</el-button>
    </el-header>
    <!-- 页面主体区域 -->
    <el-container>
      <!-- 侧边栏 -->
      <!-- 利用三元运算,确定侧边栏的宽度,isCollapse为关着的(ture)就为64px -->
      <el-aside :width="isCollapse ? '64px' : '200px'">
        <div class="toggle-button" @click="toggleCollapse">|||</div>
        <!-- 侧边栏菜单区域 -->
        <!-- unique-opened每次只开一个; :collapse="isCollapse"绑定是否折叠; :collapse-transition="false"关闭折叠动画 -->
        <!-- router表示为侧边栏开启路由模式 -->
        <!-- :default-active="activePath"实现点谁激活谁,谁高亮 -->
        <!-- data先是空串,点击谁,就this.activePath = window.sessionStorage.getItem('activePath') -->
        <el-menu background-color="#333744" text-color="#fff" active-text-color="#409EFF" unique-opened :collapse="isCollapse" :collapse-transition="false" router :default-active="activePath">
          <!-- 一级菜单 -->
          <!-- :index="item.id + '' 动态绑定索引,实现点击哪个,哪个展开.item.id为int,+'' 就变成string了-->
          <!--  v-for="item in menulist"从data中menulist遍历获取值,并渲染,根据id获取 -->
          <el-submenu :index="item.id + ''" v-for="item in menulist" :key="item.id">
            <!-- 一级菜单的模板区域 -->
            <template slot="title">
              <!-- 图标 -->
              <!-- 绑定data里的iconsObj数组对象,遍历并赋值 -->
              <i :class="iconsObj[item.id]"></i>
              <!-- 文本 -->
              <span>{{item.authName}}</span>
            </template>

            <!-- 二级菜单 -->
            <!-- v-for="subItem in item.children"找一级目录的孩子 -->
            <!-- 侧边栏开启路由模式后,index="'/' + subItem.path"表示每个二级菜单跳转的地址,且前面需要手动 + '/' -->
            <!--  @click="saveNavState('/' + subItem.path)"保存导航链接的状态,其中'/' + subItem.path为参数,传递到下面的方法中 -->
            <el-menu-item :index="'/' + subItem.path" v-for="subItem in item.children" :key="subItem.id" @click="saveNavState('/' + subItem.path)">
              <template slot="title">
                <!-- 图标 -->
                <i class="el-icon-menu"></i>
                <!-- 文本 -->
                <span>{{subItem.authName}}</span>
              </template>
            </el-menu-item>
          </el-submenu>
        </el-menu>
      </el-aside>
      <!-- 右侧内容主体 -->
      <el-main>
        <!-- 路由占位符 -->
        <router-view></router-view>
      </el-main>
    </el-container>
  </el-container>
</template>

<script>
export default {
  data () {
    return {
      // 左侧菜单数据
      menulist: [],
      iconsObj: {
        125: 'iconfont icon-user',
        103: 'iconfont icon-tijikongjian',
        101: 'iconfont icon-shangpin',
        102: 'iconfont icon-danju',
        145: 'iconfont icon-baobiao'
      },
      // 是否折叠
      isCollapse: false,
      // 被激活的链接地址
      activePath: ''
    }
  },
  created () {
    this.getMenuList()
    this.activePath = window.sessionStorage.getItem('activePath')
  },
  methods: {
    logout () {
      window.sessionStorage.clear()
      this.$router.push('/login')
    },
    // 获取所有左侧的菜单
    async getMenuList () {
      const { data: res } = await this.$http.get('menus')
      // 发送请求的状态码不为200,就返回错误信息
      if (res.meta.status !== 200) return this.$message.error(res.meta.msg)
      // 为200,就为数组赋值
      this.menulist = res.data
      console.log(res)
    },
    // 点击按钮，切换菜单的折叠与展开
    toggleCollapse () {
      this.isCollapse = !this.isCollapse
    },
    // 保存链接的激活状态,activePath为上方调用方法传过来的参数,即'/' + subItem.path
    saveNavState (activePath) {
      window.sessionStorage.setItem('activePath', activePath)
      this.activePath = activePath
    }
  }
}
</script>

<style lang="less" scoped>
.home-container {
  height: 100%;
}
.el-header {
  background-color: #373d41;
  // 左右贴边对齐
  display: flex;
  justify-content: space-between;
  // 去掉左侧空间
  padding-left: 0;
  // 按钮居中
  align-items: center;
  color: #fff;
  font-size: 20px;
  // 嵌套写法
  > div {
    // 图片纵向居中
    display: flex;
    align-items: center;
    span {
      // 设置图文间距
      margin-left: 15px;
    }
  }
}

.el-aside {
  background-color: #333744;
  .el-menu {
    // 清除边框线
    border-right: none;
  }
}

.el-main {
  background-color: #eaedf1;
}

.iconfont {
  margin-right: 10px;
}

.toggle-button {
  background-color: #4a5064;
  font-size: 10px;
  line-height: 24px;
  color: #fff;
  text-align: center;
  letter-spacing: 0.2em;
  cursor: pointer;
}
</style>
